Wire rope lubricant



3,029,203 WIRE ROPE LUBRICANT Troy L. Cantrell, Drexel Hill, and Earl E. Fisher, Glenoiden, Pa, and John G. Peters, Audubon, N..l., assignors to Gulf Research dz Development Company, Pittsburgh, Pa, a corporation of Delaware No Drawing. Filed st. 6, 1959, Ser. No. 844,620 5 Claims. (Cl. 252*37) This invention relates generally to lubricating com positions and more particularly to lubricants for wire rope.

A fully satisfactory wire rope lubricant should be capable of resisting conditions that lead to serious corrosion. Such conditions prevail in many places where wire rope is used. For example, in the steel industry Wire rope is used extensively as an integral part of machines, ore bridges, blast furnaces, conveyors, loaders, car dumpers, cranes and other devices where conditions conducive to corrosion due to extremes of weather, dust, dirt, fumes and water are generally prevalent. Likewise, in the petroleum industry wire rope is used as a component of drilling machinery that is subjected to the corrosive effects of exposure to weather extrema, various types of corrosive drilling fluids and the corrosive atomosphere found in wells.

It is important that wire rope lubricants perform well over a wide range of temperature conditions. Wire rope in service is subjected to the extremes of Weather found the world over. Therefore, it is necessary that the lubricant does not have a tendency to chip, peel or crack during cold weather so as to expose the steel wires to the atmosphere and consequent corrosion. On the other hand, there must be no tendency to drip or flow when higher temperatures are encountered.

A lubricant adapted for lubricating wire rope should provide a strongly adhesive film which will not be removed by the normal rubbing and scraping against sheaves, drums and the like. Neither should it be capable of removal by the washing action of water, or by salt spray when used to lubricate wire ropes in marine service.

Because high unit pressures are found to exist between the wires and strands of wire rope when in service, the lubricant should possess extreme pressure properties. The internal wires and strands must be protected from friction resulting from high unit pressures as well as external surfaces. This, of course, requires that the lubricant have good penetrability.

We have now discovered a composition which uniquely fulfills all or" the above-mentioned requirements. Such composition is one comprising about 30 to about 50 percent by weight of a blown asphalt, about 20 to about 40 percent by weight of a petroleum wax, about 5 to about 9 percent by weight of lead naphthenate and the remainder a mineral lubricating oil having a viscosity of about 1000 to about 3500 SUS at 100 F.

The asphalt'used in the lubricating composition of the invention is a blown asphalt obtained by air-blowing the residuum of distillation products of certain types of petroleum. Although blown asphalts of this type may be used generally, a preferred class of asphalts is one having a penetration of about 10 to about 30 under a load of grams for 5 seconds at 77 F. in accordance ice with the ASTM Standard Test Method designated D 5-52. Particularly suitable are asphaltshaving an ASTM penetration of about 15 to about 20 under the above conditions. The asphalt comprises about 30 to about 50 percent by weight of the total composition.

Wax which is suitable for the purposes of this invention can be obtained from Pennsylvania, East Texas, Mid-Continent and other such crude oils. It can be obtained either from distillate or residual fractions. Suitable type materials are petrolatum, slack wax, scale wax, parafiin wax, plate wax and the like. Preferred waxes or blends thereof are those having a melting point of about F.-to about F. The wax component is employed in a proportion which will impart improved lubricity to the composition as well as pliability at temperatures below 15 F. Ordinarily, wax in proportions of about 20 to about 40 percent by weight of the total composition will achieve these purposes.

The lead naphthenate component of this invention is a known material and is commercially available. It can be readily prepared by conventional methods such as by reaction of alkali naphthenates with lead salts, or by the direct reaction of naphthenie acids with lead oxides, hydroxides or acetates. Chemically, naphthenic acids are monocarboxylic acids of the naphthene (cycloalkane) series of hydrocarbons. The commercially available naphthenic acids are mixtures of the lower members of the series in the range of about seven to fourteen carbon atoms per molecule, and are obtained by caustic soda extraction of naphtha, kerosene, and gas oil. The commercial acids currently available possess an average molecular Weight between about 200 and about 275 and the predominating type formulas are CnH2n-202 and CnH2n402. For the purposes of the present invention, commercially obtainable naphthenic acids. can be suitably employed in the preparation of the lead naphthenate. The lead naphthenate comprises about 5 to about 9 percent by weight of the total composition.

The mineral oil component of this invention should be a petroleum oil of lubricating grade. It should have low volatility at temperatures between about 200 F. and about 350 F. since lubricating compositions are normally applied to wire rope at these temperatures. Furthermore, it should not volatilize at the higher temperatures normally encountered in wire rope service. The mineral oil component may be derived from paraffinic, coastal or naphthenic type crude oils and may be solvent treated, acid treated or otherwise refined and should have a viscosity of about 1000 to about 3500 Saybolt Universal Seconds at 100 F. Preferred mineral oils are those having a viscosity of about 1500 to about 2000 Saybolt Universal Seconds at 100 F. The mineral oil component comprises the remainder of the composition. In most instances, the mineral oil comprises about 10 to about 40 percent by weight of the total composition.

Compositions of this invention can be prepared by the following general blending procedure:

A desired amount of blown asphalt, for example 40 percent by weight, is heated to about 350 F. until the material is melted, and is then introduced into a kettle equipped with means for agitation. An appropriate quantity of mineral lubricating oil, for example 22.5 percent by weight, is then pumped into the kettle which is kept at a temperature above 250 F. to facilitate blending.

After all the oil has been added, the temperature of the kettle is cooled to about 250 F. The petroleum wax component in melted form is then added to the kettle in the desired proportion, for example 30 percent by weight. This is followed by the addition of a proper proportion, for example 7.5 percent by weight, of previously melted lead naphthenate. The contents of the kettle are then stirred for about two hours at 250 F. to achieve thorough mixing and homogenization.

A specific example of a wire rope lubricating composition of this invention comprises:

Example 1 Component: Percent by weight .Air-blown petroleum asphalt having an AST M a penetration at 77 F. of 20 40 Paraflin wax, melting point, 132.5 F 30 1900 SUS at 100 F., coastal distillate 22.5 Lead naphthenate 7,5

Typical characteristics of the above composition of this invention are as follows:

Gravity: API 16.2. Viscosity, furol: sec., 210 F 171.1. Dropping point: F 146.

Brittle point: F Below --40.

The dropping point as given above is that temperature at which the wire rope lubricant will actually drip from a wire rope. The brittle point is the lowest temperature to which the lubricant can be subjected without cracking, chipping or flaking oif the steel wire.

In order to evaluate the lubricating properties of the compositions of this invention, comparative tests were made between the composition of Example I and a well known commercial wire rope lubricating composition of the prior art.

Since the extreme pressure characteristics of a wire rope lubricant are particularly important from the standpoint of proper lubricating performance, the test cornp sitions were subjected to the 4-ball film breakdown test. This test is conducted in an apparatus wherein three steel balls are securely fastened so that rotation is impossible. A fourth steel ball in a rotating spindle is placed so that it is entirely supported by the other three balls, thus forming a pyramid. The three immobile steel balls and the rotating single steel ball are forced into contact with each other in response to a vertically applied lever load. Sufficient test lubricant is poured into a reservoir to cover the three lower balls at a predetermined length. The duration of each run is 60 seconds at a spindle speed of 1800 rpm. The lever load is increased in small increments until the lubricant under test starts to allow excessive scarring or gouging of the three stationary balls. The lever load at which this occurs is taken as the extreme pressure rating. I It is a measure of the ultimate load-carrying capacity of the test lubricant before the oil film ruptures. The results are as follows:

Ratingmaximum Composition: load, kg. Commercial pro 52 Example I composition 76 4 scar being measured to the closest 0.01 mm. and averaged. The results' of the test were as follows:

Average scar diameter,

Composition: mm. Commercial product 0.783 Example I composition 0.495

The resistance to corrosion, together with the adhesive characteristics of Example I, was evaluated by means of method 4001.1 of Federal Test Method Standard No. 791, better known as the Protection, Salt Spray (Fog) Test. In conformance therewith, steel test panels were suspended in a chamber which was kept at a constant temperature of F. and in an atmosphere of a finely divided, wet, dense fog made up of a 4 percent sodium chloride solution in distilled water. At the end of 14 days, there was no evidence of pitting or rust on the test panels and adherence of the test lubricant to the panels was excellent.

In a further test of adherence, several steel panels, coated with the composition of Example I, were totally immersed in a 4 percent salt water solution held at a temperature of 77 F. After 30 days, thetest composition was still adhering rigidly.

Other examples of the herein described invention with similar properties and test results to that of Example I are as follows:

Example II Percent by Component: weight Air-blown petroleum asphalt having an ASTM penetration at 77 F. of 25 45.0 Parafi'in Wax, melting point, 132.5 F 20.0 Petrolatum, melting point, 158 F 10.0 1900 SUS at F., coastal distillate 17.5 Lead naphthen 7.5

Example III Component: Percent by weight Air-blown petroleum asphalt having an ASTM penetration at 77 F. of 25 40 Paraffin wax, melting point, 132.5 F. 20 Petrolatum, melting point, F. 10 1900 SUS at 100 F., coastal distillate 22.5 Lead naphthenate 7.5

This application is a continuation-in-part of our copending application Serial No. 680,419 filed August 26, 1957, now abandoned.

The invention is not to be limited by the specific examples given, but only such limitations should be imposed as are indicated in the appended claims, wherein it is intended to claim the invention as broadly as the prior art permits.

We claim:

1. A lubricating composition suitable for wire rope lubrication consisting essentially of about 30 to about 50 percent by 'weight of blown asphalt having an ASTM penetration of about 10 to about 30 under a load of 100 grams for 5 seconds at 77 F., about 20 to about 40 percent by weight of petroleum wax having a melting point of about 125 F. to about F., about 5 to about 9 percent by weight of lead naphthenate and the remainder a mineral lubricating oil having a viscosity of about 1000 to about 3500 SUS at 100 F.

'2. A lubricating composition suitable for wire rope lubrication consisting essentially of about 30 to about 50 percent by weight of a blown asphalt having an ASTM penetration of about 10 to about 30 under a load of 100 grams for 5 seconds at 77 F., about 20 to about 40 percent by weight of petroleum wax having a melting point of about 125 F. to about 160 F., about 5 to about 9 percent by weight of lead naphthenate and about 10 to about 40 percent mineral lubricating oil having a viscosity of about 1000 to about 3500 SUS at 100 F.

3. A lubricating composition suitable for wire rope lubrication containing the following constituents in the following proportions:

Component: Percent by weight Air-blown asphalt having an ASTM penetration at 77 F. under load of 100 grams for seconds of 20 40 Paratfin wax, melting point, 132.5 F. 30 1900 SUS at 100 F., coastal distillate 22.5 Lead naphthenate 7.5

4. A lubricating composition suitable for'wire rope lubrication containing the following constituents in the following proportions:

Component: Percent by weight Air-blown asphalt having an ASTM penetration at 77 F. under load of 100 grams for 5 secends of 25 45 Parafiin wax, melting point, 132.5 F. 20 Petrolatum, melting point, 158 F. 1900 SUS at 100 F., coastal distillate 17.5 Lead naphthenate 7.5

5. A lubricating composition suitable for wire rope lubrication containing the following constituents in the following proportions:

Component: Percent by weight Air-blown petroleum asphalt having an ASTM penetration at 77 F. under a load of 100 grams for 5 seconds of Paraifin Wax, melting point, l32.5 F. 20 Petrolatum, melting point, 150 F. 10 1900 SUS at F., coastal distillate 22.5 Lead naphthenate 7.5

References Cited in the file of this patent UNITED STATES PATENTS 

1. A LUBRICATING COMPOSITION SUITABLE FOR WIRE ROPE LUBRICATION CONSISTING ESSENTIALLY OF ABOUT 30 TO ABOUT 50 PERCENT BY WEIGHT OF BLOWN ASPHALT HAVING AN ASTM PENETRATION OF ABOUT 10 TO ABOUT 30 UNDER A LOAD OF 100 GRAMS FOR 5 SECONDS AT 77*F., ABOTU 20 TO ABOUT 40 PERCENT BY WEIGHT OF PETROLEUM WAX HAVING A MELTING POINT OF ABOUT 125*F. TO ABOUT 160*F., ABOUT 5 TO ABOUT 9 PERCENT BY WEIGHT OF LEAD NAPHTHENATE AND THE REMAINDER A MINERAL LUBRICATING OIL HAVING A VISCOSITY OF ABOTU 1000 TO ABOTU 3500 SUS AT 100*F. 